﻿using Apewer;
using Apewer.Internals;
using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;

namespace Apewer.Network
{

    /// <summary>TCP 客户端。</summary>
    public class TcpClient
    {

        #region event

        /// <summary>Exception。</summary>
        public Event<Exception> Excepted { get; set; }

        /// <summary>已发送数据。</summary>
        public Event<byte[]> Sent { get; set; }

        /// <summary>已接收数据。</summary>
        public Event<byte[]> Received { get; set; }

        /// <summary>已连接。</summary>
        public Event Connected { get; set; }

        /// <summary>已断开。</summary>
        public Event Closed { get; set; }

        #endregion

        #region definition

        private Thread _listener = null;
        private Thread _provider = null;
        private Socket _socket = null;
        private Queue<byte[]> _queue = null;

        // private AutoResetEvent _are = null;

        private bool _break = false;
        private int _timeout = 0;

        private string _localip, _remoteip;
        private int _localport = 0, _remoteport = 0;

        private bool _background = true;

        /// <summary></summary>
        internal object Tag { get; set; }

        /// <summary>构造函数。</summary>
        public TcpClient()
        {
            RemoteIP = "127.0.0.1";
            RemotePort = 0;
        }

        /// <summary>构造函数。</summary>
        public TcpClient(string ip, int port, int timeout = 0)
        {
            RemoteIP = ip;
            RemotePort = port;
            Timeout = timeout;
        }

        #endregion

        #region accessor

        /// <summary>获取或设置监听线程是否为后台线程，默认为“是”。</summary>
        public bool Background
        {
            get { return _background; }
            set
            {
                _background = value;
                try { if (_listener != null) _listener.IsBackground = value; }
                catch (Exception ex) { Excepted?.Invoke(this, ex); }
            }
        }

        /// <summary>获取或设置远程计算机的 IP 地址。</summary>
        public string RemoteIP
        {
            get { return _remoteip; }
            set
            {
                string ip = value;
                if (!NetworkUtility.IsIP(ip)) ip = NetworkUtility.Resolve(ip);
                if (!NetworkUtility.IsIP(ip)) ip = "127.0.0.1";
                _remoteip = ip;
            }
        }

        /// <summary>获取或设置远程计算机的 TCP 端口号。</summary>
        public int RemotePort
        {
            get { return _remoteport; }
            set
            {
                int port = value;
                if (port < 0) port = 0;
                if (port > 65535) port = 65535;
                _remoteport = port;
            }
        }

        /// <summary>获取或设置本地计算机的 IP 地址。</summary>
        public string LocalIP
        {
            get { return _localip; }
            private set { _localip = string.IsNullOrEmpty(value) ? "" : value; }
        }

        /// <summary>获取或设置本地计算机的 TCP 端口号。</summary>
        public int LocalPort
        {
            get { return _localport; }
            private set
            {
                int port = value;
                if (port < 0) port = 0;
                if (port > 65535) port = 65535;
                _localport = port;
            }
        }

        /// <summary>获取或设置超时时间。</summary>
        public int Timeout
        {
            get { return _timeout; }
            set { _timeout = (value > 0) ? value : 0; }
        }

        /// <summary>开始连接，并初始化发送队列。</summary>
        public void Start(bool inBackground = false)
        {
            Close(false);
            _queue = new Queue<byte[]>();

            if (!inBackground)
            {
                _provider = new Thread(Provider);
                _provider.IsBackground = true;
                _provider.Start();
                return;
            }

            Provider();
            // _are.WaitOne(1000);
        }

        /// <summary>断开连接。</summary>
        /// <param name="event">是否引导 Closed 事件。</param>
        public void Close(bool @event = true)
        {
            CloseThread(ref _provider);
            CloseThread(ref _listener);
            CloseSocket();
            CloseQueue();
            _queue = null;
            // _are = null;
            if (@event) Closed?.Invoke(this);
        }

        /// <summary>向服务端发送数据。</summary>
        /// <param name="bytes">字节数组。</param>
        public bool Send(byte[] bytes)
        {
            if (_socket != null)
            {
                _queue.Enqueue(bytes);
                return true;
            }
            else
            {
                var ex = new SocketException(10057);
                Excepted?.Invoke(this, ex);
                return false;
            }
        }

        /// <summary>是否已连接。</summary>
        public bool Online
        {
            get
            {
                try { if (_socket != null) return _socket.Connected; }
                catch (Exception ex) { Excepted?.Invoke(this, ex); }
                return false;
            }
        }

        #endregion

        #region logic

        private void Listener()
        {
            var buffer = new byte[TcpBuffer.Size];
            var length = 0;
            while (true)
            {
                try
                {
                    if (_socket.Poll(50, SelectMode.SelectWrite))
                    {
                        _socket.Blocking = true;
                        length = _socket.Receive(buffer);
                        if (length > 0)
                        {
                            var bytes = new byte[length];
                            Array.Copy(buffer, bytes, length);
                            Received?.Invoke(this, bytes);
                        }
                        else
                        {
                            if (_socket != null) break;
                        }
                    }
                }
                catch (SocketException ex)
                {
                    if (ex.ErrorCode != 10060) Excepted?.Invoke(this, ex);
                    if (ex.ErrorCode == 10054) break;
                }
                catch (Exception ex)
                {
                    Excepted?.Invoke(this, ex);
                    // break;
                }
            }
            if (_provider != null)
            {
                if (_provider.IsAlive) _provider.Abort();
                _provider = null;
            }
            if (_socket != null)
            {
                _socket.Disconnect(true);
                _socket.Close();
                _socket = null;
            }
            CloseThread(ref _provider);
            CloseSocket();
            CloseQueue();
            Closed?.Invoke(this);
        }

        private void Provider()
        {
            _break = false;
            _socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            if (_timeout > 0) _socket.SendTimeout = _timeout;
            if (_timeout > 0) _socket.ReceiveTimeout = _timeout;
            //_are = new AutoResetEvent(false);

            try
            {
                _socket.Blocking = true;
                _socket.Connect(_remoteip, _remoteport);
                if (_socket.Connected)
                {
                    _socket.SendBufferSize = TcpBuffer.Size;
                    _socket.ReceiveBufferSize = TcpBuffer.Size;
                    var rep = (IPEndPoint)_socket.RemoteEndPoint;
                    var lep = (IPEndPoint)_socket.LocalEndPoint;
                    _remoteip = rep.Address.ToString();
                    _localip = lep.Address.ToString();
                    _localport = lep.Port;

                    Connected?.Invoke(this);
                    _listener = new Thread(Listener);
                    _listener.Start();
                    //  _are.Set();
                }
                else
                {
                    Close();
                    return;
                }
            }
            catch (Exception ex)
            {
                Excepted?.Invoke(this, ex);
            }

            while ((!_break) && (_socket != null))
            {

                if (_queue.Count > 0)
                {
                    var bytes = _queue.Dequeue();
                    if (bytes.Length > 0)
                    {
                        try
                        {
                            _socket.Send(bytes);
                            Sent?.Invoke(this, bytes);
                        }
                        catch (Exception ex)
                        {
                            Excepted?.Invoke(this, ex);
                        }
                    }
                    else
                    {
                        Thread.Sleep(1);
                    }
                }
            }
        }

        private void CloseSocket()
        {
            if (_socket != null)
            {
                try
                {
                    _socket.Disconnect(false);
                    _socket.Close();
                }
                catch (SocketException ex) { Excepted?.Invoke(this, ex); }
                catch (Exception ex) { Excepted?.Invoke(this, ex); }
                _socket = null;
            }
        }

        private void CloseThread(ref Thread thread)
        {
            if (thread != null)
            {
                if (thread.IsAlive) thread.Abort();
                thread = null;
            }
        }

        private void CloseQueue()
        {
            if (_queue != null) _queue.Clear();
        }

        #endregion

    }
}
